Theories of Liquids

Since Henderson's review ( 1) of liquids appeared in the Annual Review of Physical Chemistry in 1964 , there have been many books and review articles written about liquids , and one of the tasks in writing yet another review at this time is to decide which topics have been sufficiently reviewed already. Among the topics which might have been considered for review here are computer studies of liquids , equations of state, critical phenomena, the melting transition, solutions , transport phenomena, quantum liquids , surface tension, water , distribution function theory , liquid m etals , and inelastic and elastic scattering in liquids. For a variety of reasons , including a limitation of space, we have chosen to review only the first four of these topics , although very special aspects of some of the other subjects do appear under other headings. We would like to point out that all of these last topics have been reviewed recently, and indeed solutions (2) are reviewed in another article in this volume. Among the many articles which have appeared in the last 4 or 5 years on transport phenomena are recent reviews by Rice, Boon & Davis (3) and by Nicolis and associates (4). Quantum liquids are currently receiving much attention and are discussed , for example, in books by Pines & Nozieres (5) and by Brewer (6). Studies of surface tension have been reviewed by Buff & Lovett (7). Recent reviews on water are contained in the book , The Structure and Properties of Water by Eisenberg & Kauzmann (8) and in an article by Conway (9). Discussions of recent developments in distribution function theory, including the improved Percus-Y evick (PYII) and improved hy­ pernetted-chain ( HNCII) integral equations ( 10) are to be found in an article by Rushbrooke ( 1 1) and in a book by Cole ( 12). Although we shall not review this topic , we wish to m ention that one problem which is currently of interest is that of obtaining the intermolecular pair potential from the experim entally d etermined radial distribution function by way of the distribution function theory of liquids ( 13 , 14). R ecent reviews of liquid m etals include the book Liquid Metals by March (15) and the conference proceedings , The Properties of Liquid Metals, edited by Adams, Davis & Epstein ( 16). Finally , in our list of reviews of topics not covered here are the reviews of inelastic and elastic scattering from liquids. The development of the laser has resulted in greatly improved techniques ( 17-19) for studies of light scattering , and these new techniques will un-